Excavator



April 3G, 1935. F. H. BAKKER EXCAVATOR Filed Deo.

/NVENTOR MMM Patented Apr. 30, 1935 laterz UNITED Fil-TME EXCAVATURFrederik Hendrik Bakker, The Hague, Netherlands Application December 19,1933, Serial No. 703,067

6 Claims.

This invention relates to a scraper or excavator bucket of thebottomless type which is drawn to and fro over the ground by means ofseveral cables and the scraper bucket has means to regulate the depthsofexcavation in every point of the path during the working of the same.This device regulates the depth of excavation in a fashion similar tothat set forth in my Dutch Patent No. 31,138.

When the excavator bucket is drawn forward during the working period thedepth or extent of excavation can be regulated by the use of a rockingknife. This rocking knife can be placed in various positions vby theoperation of several cables used with excavator buckets of this type'.These cables are operated -at different times in order to x the knife inits desired position. The cables are referredl to as steering cables,pulling cables and back pulling cables. When the bucket is full or whenit is desired; to discontinue the excavationwith the` bucket, thesteering cable is braked. The braking of this cable results in, a forcebeing applied on the bucket contrary to the pulling force in the pullingcable and the resulting force on the bucket is equivalent to the pullingforce in the pulling cable, minus the brakin g force in the steeringcable. Since the braking force represents a loss of power, it isnecessary, in order to have the device function as eiciently aspossible, to reduce the loss of power to a minimum. p

It is therefore an object of this invention to reduce the loss of powerto a minimum.

This is accomplished by the use of a rocking vknife which can be placedin diierent positions during the workingof the machine. This is done bythe braking of the steering cable or the back pulling cable which causesthe knife to move into its proper position notwithstanding the pressureof the earth on the knife which tends to force the same into anotherposition.

It is further to be noted that the rocking knife may be locked in anumber of intermediate positions as well as extreme positions which arenot changed by the pressure of the earth on said knife. A The inventionis set forth in the drawing which discloses two types ofexcavatorvbuckets. Figure l discloses a side view of a scraper bucket inwhich the digging knife may be placed in two extreme positions. Fig. 2discloses a cross section of a steering coupling which may be used inplace of the wheel shown in Figure 1 which allows the knife to be lockedin several intermediate positions. Fig. 3 shows a longitudinal sectionof the steering coupling shown in Fig. 2.

The scraper bucket l is drawn over the ground during the working periodof the device by means of a pulling cable 2. A U-shaped knife t having acutting edge 3 is pivoted to said scraper bucket i atit, so that it canbe placed in several digging positions. A connecting rod 'l is coupledby means of an axle F to the top end 5 of the knife 4. The opposite endof this connecting rod l is connected to a pin il whichis rigidlyconnected to a rotatable cable wheel 9. This cable wheel is movablearound an axle lli, which axle is rigidly connected Vto the side platesil of the scraper bucket i. The steering cable i2 and the back pullingcable i3 areV connected to the circumference of the wheel 9 at variouspoints to move the wheel in opposite directions. The ends of Y the pinmove in circular slots in the side plates i l. These slots contain theends l5 and IB which limit the extent of the movement of the pin 8 andtherefore nx the extreme positions for the digging knife.

l The operation of this device is as follows: During the working periodthe back pulling cable I 3 is braked which causes the cable Wheel 9 toturn in a counterclockwise direction. The movement of the cable wheel 9in a counterclockwise direction causes the connecting rod l' to move tothe left and the knife l which is rigidly pivcted to said connecting rodfalls forward and thereby allows the cutting edge 3 to dig intothe soilof the earth. This position of the cutting edge of the knife isindicated in Fig. I of the drawing by dotted lines. Y

l It may be desirable'during the working period to have the cutting edgeof the knife withdrawn 'from the ground This is accomplished by brakingthe steering cable l2. The braking of the steering cable causes thecable wheel 9 and the pin 8 to move in a clockwise direction. Thismovement of the wheel and pin causes kthe connecting rod l to move tothe right. This operation therefore causes the knife 4to fall backwardsinto a position as indicated in Fig, 1 of the drawing by full lines.

The radius of the circle made by the ,movement of the pin 8 mounted onthe cable wheel 9 must be chosen in such a way that the pin passes for ashort distance during the last portion of the rocking motion animaginary connecting line of the points 'to iii. In its extremepositions the pin kpasses the dead points of this imaginary line and asa result it cannot be dislocated by pressure or tension in. theconnecting rod This particular feature also allows the release of thebraking force which might be made to the steering cable or the backpulling cable.

In case it is desirable to position the knife in intermediate positions,the cable Wheel is replaced by a steering coupling such as the deviceshown in Figs. 2 and 3. It is particularly desirable to place the knifein intermediate positions where` the excavation is made on a brokenslope or is passed over thin layers of earth. In this steering couplingthe axle l@ is replaced by a ratchet wheel il' which has teeth. Theteeth of this ratchet wheel are positioned so that 'they point in aclockwise direction. The ratchet wheel is suitably connected totheplates `Ii'of the scraper bucket by means of a Xed axle with key andkeyway or, as shown in the drawing, by several bolts I8. Around theratchet wheel I'I are formed circular running surfaces which aresurrounded by two circular plates IS rigidly connected to cach other bymeans of the locks 2li, bolts 2i and 222 and the pin 8. The paWls 23 ofthe ratchet wheel construction have tail pieces Zilwhich can pivot aboutthe bolts 22 and pin 8. These pavvls are ordinarily urged against theratchet wheel il by means of the springs 25 whichmay be connected to thebolts ZI in the blocks 28. While the number of these pawls may bevaried, the drawing discloses the use of only three.

Arpund the plates 49 previously referred to there is rotated the pulleyring 25 which has in its outer circumference cable grooves upon whichare secured the ends of the steering cablev I2 and the backpulling cableI3. The ends cf these two-cables are wound around said ring in oppositedirections so that the ring may be turned in a clockwise orcounterclockwise direction, according to the desires of the operator.The amount of rotation of this ring 25 in relation to the plates It islimited by the cams 2l on the blocks 2d which cams alternatively pushagainst the points 28 and 29 of the ring 2E.

The cams 3B are mounted on the inner surface of the ring 28 in order topush against the tail pieces 24 of the pawls 23 when the ring E@ isturned in a counterclockwise direction. If the ring is turned further tothe left, the cam 3@ pushes the tail pieces 2li inwardlyv against thepressure of the springs 25 and moves the pawls 23 free from the ratchetwheel Il.

The operation of this type of scraper is as follows: When the bucket ispulled forward and no braking force is exerted on the steering cable oron the back pulling cable the soil of the ground pushes against thecutting edge 3 of the blade 4 and causes this knife to fall forward (seedotted lines of Fig. l). As a result of this, the connecting rod 'I andthe pin 8 are pulled forward. During this movement to the left, or in acounterclockwise direction, the tail pieces 2e of the pawls Z3 becomefree from the cams 3o. After this movement the springs 25 press thesetail pieces outwardly and rcause the pawls to be pressed Ybetween theteeth of the ratchet wheel il. This results in the placing of theknife'in a fxedvinterrnediate position which may not be changed by thepressure of the soil.

If it is desired to dig a deeper out in the ground the back pullingcable is braked. This causes the ring ZS to turn to the left and theearns SG to press the tail pieces 2d inwardly. This results also in thepawl becoming free from the ratchet wheel I1. Due to the tension of theconnecting rod 'i caused by the pressure of the ground on the cuttingedge 3 of the knife 4, the pin 8 is also moved to the left and thiscauses the tail pieces 24 to become free from the cams 30 so that thepawls 23 catch behind the teeth of,

the ratchet Wheel I'I. By continuous or'repeated manipulation of thedevice as herein mentioned, the digging knife can be made to fallforward in its extreme position.

It also might be desired during the operation of the device that therebe no digging into the earth. This is accomplished by braking thesteering cable which causes the ring 26 to turn to the right until thepoints 28 on said ring press against the earns 2i' of the blocks 2E).Upon further rnovernent of the rings 26 the blocks 20A and the pin 3 aremoved to the right and the pawls slide over the teeth of the ratchetWheel I'I. As soon as the braking force in the steering cable stops, thepulling force of the connecting rod fi pulls the pin 8 to the left untilthe pawls engage the teeth of the ratchet Wheel and lock the knife in alfixed position such as shown in the full lines for the knife in Fig, 1of the drawing.

When it is desired to pull the bucket backwards, the back pulling cableI3 first turns the ring 25 .to the left which results in the pawls 23being lifted from the ratchet wheel I'I. The points 29 of the ring 26then come into contact with the cams 21 and pin 8 which are likewisecaused to rotate to the left. The rotation of the pin 3 to the' left is.accomplished against the pressure of the connecting rod 1 created by thepressure of the ground against the back side of the knife4 4. Asa resultof this constant pulling force in the back pulling cable I3, the ring 26and the pin 8 are turned into the eXtreme position whereby the knife ispressed into its forward extreme position so that the back side of theknife cannot dig itself into the ground.

y The detailed description above describes the invention proposedbutapplicant desires it. to be known that his device may be completed-andoperated by other types of mechanism.

What I claim is:-

l.. In a digging scraper bucket of the bottomless-type, cable means formoving said scraper over the ground, a digging knife pivotally mountedupon said bucket and means'for rocking said digging knife to severalangular positions with respect to the horizontal and means connectedwith said rocking means for locking said digging knife in its desireddigging position, all of said means being operable during the movementof the scraper bucket over the ground.

In a digging scraper bucket of the bottom- .less type, cable means formoving said bucket over the ground, a rocking knife pivotally mounted onsaid bucket, means for moving said rocking knife to several angularpositions with respect to the horizontal, and means connected withsaidrocking means forlocking said knife in its desired digging position,all of said means being operableduring the movement of the scraperbucket over the ground. Y

3. In a digging scraper bucket of the bottomless type, cable means forcoming said bucket over the ground, a U-shaped digging knife pivotallymounted on said bucket, means for rocking said U-shaped digging knife toseveral angular positions with respect to the horizontal, and meansconnected with said rocking means for locking saidv knife in its desireddigging position, all of said means being .operable ,duringv themovement of the scraper bucket over the ground.

4. In a digging scraper bucket of the bottomless type, cable means formoving said bucket over the ground, a digging knife pivotally mountedupon said bucket, an oscillating cable Wheel movable by a pair of cablesfor moving said knife into several angular positions with respect to thehorizontal, and means connected with said cable Wheel for locking saidknife in the desired digging position, all of said means being operableduring the movement of the bucket over the ground.

5. In a digging scraper bucket of the bottomless type, cable means formoving said bucket over the ground, a digging knife pivotally mountedupon said bucket, means for rocking said knife into several angularpositions with respect to the horizontal, and a paWl and ratchetmechanism connected with said. rocking means for locking said knife inthe desired angular position, all of said means being operable duringthe movement of the bucket over the ground.

6. In a digging scraper bucket of the bottomless type, cable means formoving said bucket over the ground, a digging knife pivotally mountedupon said bucket, an oscillating cable Wheel movable by a pair of cablesfor moving the knife about its pivot into a desired angular positionWith respect to the horizontal, and a pavvl and ratchet means forlocking said knife in said desired position, all of said means beingoperable whereby said knife may be moved into several different angularpositions and locked therein during the movement of the bucket over theground.

FREDERIK HENDRIK BAKKER..

